The present invention is directed to a method and apparatus for producing vapor from a liquid using laser energy, and particularly to a laser fired boiler of a steam generator.
Pollution of the environment in the production of steam for generating electric power and heat has become an increasing problem in recent years. The by-products of the combustion of coal released into the atmosphere and radiation leaks from nuclear power generating stations can be cited as examples. Thus, there is a need for an improved method and apparatus of producing vapor such as steam from a liquid without air pollution or radioactivity.
An object of the present invention is to provide a method and an apparatus for producing vapor such as steam from a liquid without air pollution or radio activity through the use of lasers.
This and other objects of the invention are obtained by the method of the invention for producing vapor from a liquid using laser energy which comprises the steps of providing a liquid to be vaporized in a container, directing at least one laser beam into the liquid into the container and retaining at least essentially all of the energy of the at least one laser beam in the container for vaporizing the liquid.
According to a disclosed preferred embodiment of the invention, a plurality of laser beams are directed into the liquid. The laser beams are directed so that they intersect one another in the liquid within the container. The energy of the laser beams is retained by providing a shield within the container which prevents passage of the laser beams and acts to absorb energy of the laser beams impinging thereon. The shield is in contact with the liquid within the container so as to transfer any heat in the shield to the liquid.
In the disclosed embodiment, the shield is spaced inwardly of an outer wall of a container with liquid being provided on inner and outer sides of the shield. The shield has a hollow, essentially closed form with openings therein through which the laser beams are directed for vaporizing the liquid. The shield is preferably formed in a plurality of segments which are releasably supported on the inner wall of the container.
Further, the method of the invention includes the step of replacing the liquid in the container which is vaporized. For this purpose the container has an opening in the bottom thereof through which liquid is introduced to replace the liquid in the container which has been vaporized. The method further includes the step of conveying vaporized liquid from the container. The vapor is conveyed from the container through an opening provided in the top of the container.
The method further includes the step of passing the at least one laser beam through a lens provided in the container before the laser beam enters the liquid within the container. In the disclosed embodiment of the method, the lens causes the laser beam to diverge as it passes through the liquid within the container. The liquid in the container in the disclosed embodiment is water.
The apparatus of the invention for producing vapor from a liquid using laser energy comprises a container in the form of a drum for the liquid to be vaporized. Means are provided for introducing at least one laser beam into liquid such as water provided in the container. The apparatus further includes means for retaining at least essentially all of the energy of the at least one laser beam in the container for vaporizing the liquid.
According to the disclosed form of the invention, the apparatus is a laser fired boiler of a high pressure steam generator. The container for liquid to be vaporized is a large, high strength metal drum which includes a plurality of spaced portions which are transparent to laser beams to permit a plurality of laser beams to be introduced into water provided in the drum. A shield is provided in the drum for obstructing and absorbing laser energy of the laser beams which impinge thereon. The shield is in contact with the water in the container for transferring its heat energy to the water.
The plurality of spaced transparent portions of the drum are formed by openings in the drum and lens holders which are sealingly secured to the drum about the openings. The lens holders extend from the drum to a corresponding opening in the shield within the container. The laser beams pass through respective lenses supported in the lens holders which cause the laser beams to diverge in the water within the container. The shield has a hollow essentially closed form with openings therein through which the laser beams are directed for vaporizing the liquid. To fully utilize the laser energy absorbed by the shield, liquid is provided on inner and outer sides of the shield.
These and other objects, features and advantages of the invention will become more apparent from the following description when taken in connection with the accompanying drawings which show, for purposes of illustration only, one preferred embodiment in accordance with the invention.